特殊环境下复杂水下盾构隧道管片衬砌纵向受力分析

发布时间：2019-04-16 10:22

【摘要】：随着轨道和市政领域盾构隧道的迅速发展,隧道纵向不均匀沉降问题日渐凸显,由此引发的渗水漏泥、结构破坏及内部扭曲等问题逐渐引起人们的重视。本文以此为背景,通过理论分析和数值模拟,在完善纵向等效连续化模型的基础上,进一步修正了刚度,为实际工程提供了参考。首先,考虑纵向轴力对中性轴的影响,推导了盾构隧道管片结构的纵向刚度、环缝张开量及曲率半径的表达式,并针对佛莞狮子洋147号钻孔断面进行了对比分析,验证了该计算公式的正确性,并进一步讨论了环缝长度影响系数、横向刚度有效率、错缝拼装系数对管片结构纵向刚度有效率的影响。结果表明:中性轴位置取决于等效偏心距的大小,管片结构横向刚度和错缝拼装对于提高结构纵向刚度有效率的作用显著。接着,引入联络横通道、竖井、管片壁后空洞、采空区及管片内衬开展进一步分析,建立了影响区域(-30m,30m)范围内管片结构纵向刚度有效率与位移的线性关系,分析了附属结构和特殊环境结构受力和变形,并对前述特殊情况下管片结构的纵向力学性能进行了修正。结果表明:附属结构和特殊环境能产生局部应力集中,在位移等效下,能显著改变结构的纵向刚度,且影响程度受接头型式和区段长度控制,应在特殊地段的过渡带(-10m,10m)范围进行必要的柔性处理。最后,以佛莞狮子洋隧道为对象,选取上覆或下卧层不均、地层埋深突变、岩层软硬交替等断面,计算同时考虑水土合算和水土分算情况下隧道的位移和内力分布;并以百年最高、最低水位进一步分析,分析水浮力、河流冲刷及岸边构筑物对运营期隧道的加卸载影响,探明了隧道拱顶、拱腰、拱底的变形及内力变化规律,结果表明:地层突变处会出现纵向应力突变,水下隧道的纵向轴力在纵向设计中不容忽视。论文以纵向刚度为脉络,通过公式推导、特殊地段修正及具体工程案例有限元分析,重点考察了隧道纵向沉降及纵向轴力、弯矩的变化规律,最后得到了纵向刚度有效率倍数表,弥补了目前水下盾构隧道纵向结构及变形设计的不足,具有重要的工程价值和指导意义。
[Abstract]:With the rapid development of shield tunnel in track and municipal field, the longitudinal uneven settlement of tunnel is becoming more and more prominent. The problems such as seepage and leakage of mud, structural damage and internal distortion caused by this problem have attracted more and more attention. In this paper, based on the theoretical analysis and numerical simulation, on the basis of perfecting the longitudinal equivalent continuum model, the stiffness is further modified, which provides a reference for practical engineering. Firstly, considering the effect of longitudinal axial force on the neutral axis, the expressions of longitudinal stiffness, annular joint opening and curvature radius of shield tunnel segment structure are derived, and the cross-section of bore hole No. 147 of Dongguan Lion Yang is compared and analyzed. The correctness of the formula is verified, and the effects of the influence coefficient of annular joint length, the effective rate of transverse stiffness and the assembling coefficient of staggered joints on the longitudinal stiffness of segment structure are further discussed. The results show that the position of the neutral axis depends on the equivalent eccentricity. The transverse stiffness and staggered joint assembly of the segment structure play a significant role in improving the longitudinal stiffness of the structure. Then, the linear relationship between the longitudinal stiffness efficiency and displacement in the affected area (- 30m, 30m) is established by introducing the connecting transverse channel, shaft, the cavity behind the segment wall, the goaf and the inner lining of the pipe piece to carry out further analysis, and the linear relation between the longitudinal stiffness effective rate and the displacement in the affected area (- 30m, 30m) is established. The stress and deformation of adjunct structure and special environmental structure are analyzed, and the longitudinal mechanical properties of segment structure under the above-mentioned special circumstances are modified. The results show that the subsidiary structure and special environment can produce local stress concentration. Under the equivalent displacement, the longitudinal stiffness of the structure can be significantly changed, and the influence degree is controlled by the type of joint and the length of the section. It should be in the transitional zone (- 10m,-10m) in the special section. 10m) the necessary flexible handling is carried out within the range. Finally, taking the Buddha-Dongguan Shiziyang tunnel as the object, the displacement and internal force distribution of the tunnel under the condition of soil and water combined calculation and soil and water division calculation are calculated, such as uneven overlying or underlying layer, sudden buried depth, alternation of soft and hard strata, etc. The influence of water buoyancy, river scour and bank structure on the loading and unloading of tunnel during operation is analyzed, and the deformation and internal force of arch roof, waist and bottom of tunnel are found out by the analysis of the highest and lowest water level in the last 100 years, and the influence of water buoyancy, river scour and bank structure on the loading and unloading of tunnel during operation period is analyzed. The results show that there is a sudden change of longitudinal stress in the place of stratum sudden change, and the longitudinal axial force of underwater tunnel can not be ignored in the longitudinal design. In this paper, the longitudinal stiffness is taken as the vein, through the derivation of the formula, the modification of the special section and the finite element analysis of the concrete engineering case, the variation rule of the longitudinal settlement, longitudinal axial force and bending moment of the tunnel is investigated emphatically. Finally, the table of longitudinal stiffness efficiency multiplier is obtained, which makes up for the deficiency of longitudinal structure and deformation design of underwater shield tunnel, and has important engineering value and guiding significance.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.43

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